Glowworm 18 HXI

tonygima1 · 26 Jun 2018

Hello, I've recently experienced a problem with the above boiler. Boiler is 10 years old and has become noisy. Gas engineer put Fernox F2 boiler silencer into system. This exposed a noise which sounds like drums being played inside the boiler! This only occurs when the boiler is fully surging in power, usually around 70 degrees. The HEX has been cleaned, fan replaced and now system is being cleaned with Fernox F3. The diverter valve is sticking slightly and is being replaced next week. I took a video illustrating the noise this pm after the cleaner had been applied. Here the boiler is surging before it cuts out. Can anyone identify the noise?

https://1drv.ms/v/s!Aq7r42kkeO1ngs4GzkON-AfGf-qs_A

Thanks for any advice

Tony

easyflow · 26 Jun 2018

At a good guess I would say the problem lies not with the boiler but an iron oxide blockage probably with the flow or return around the cylinder area.
Ask your plumber to run a magnet all over the the flow and return pipes in the cylinder cupboard, see if the magnet pulls at a certain point(s).

tonygima1 · 26 Jun 2018

Thanks for that, will follow that up.

MTCH · 27 Jun 2018

What was done to clean the heat exchanger?

tonygima1 · 27 Jun 2018

The burner door was removed and scale removed using a nylon brush with a mixture of strong white vinegar and limescale remover. All surfaces were smooth and scale free when the door was replaced. Now running Fernox F3 through the system for a week.

Many thanks

Tony

Gasguru · 27 Jun 2018

What's the bypass valve set to and the pump setting? If the boiler is installed correctly it should be across the flow and return after the pump...it ensures a minimum flowrate through the boiler.

45yearsagasman · 27 Jun 2018

The heat exchanger was removed and cleaned with chemicals internally I hope. Removing the cover and polishing the combustion surfaces will do SFA to reduce noise.

tonygima1 · 27 Jun 2018

Not sure about the bypass valve setting, pump is on maximum. Fernox F3 is running in system at the moment (leaving up to 7 days) to remove limescale

Gasguru · 27 Jun 2018

And you're not going to check it or post a pic of the setting?

tonygima1 · 27 Jun 2018

I'm a novice, not a plumber/gas heat engineer so not sure where bypass valve is

Gasguru · 27 Jun 2018

https://www.google.co.uk/search?q=b...8vTbAhXKN8AKHf9wCTQQ_AUICygC&biw=1280&bih=896

Hason · 28 Jun 2018

It will be a coil in the heat exchanger partly blocked, hxi heat exchanger has coils. You can not clean heat exchanger, new heat exchanger required just done 2 , I cut them open scale/debris wedged in coil.
Hopes this helps

tonygima1 · 1 Jul 2018

Many thanks for your response. Have discovered that cold feed and expansion pipes are partially blocked (used powerful magnet). Work being done next week.

ServiceNumpty · 2 Jul 2018

tonygima1 said:
Many thanks for your response. Have discovered that cold feed and expansion pipes are partially blocked (used powerful magnet). Work being done next week.

Be prepared to shell out for a new heat exchanger then. If the system was dirty as it sounds like it is, the waterways in the giannoni hex are tiny and block up very easily.

diynot

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Glowworm 18 HXI

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